/*
 * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The OpenAirInterface Software Alliance licenses this file to You under 
 * the Apache License, Version 2.0  (the "License"); you may not use this file
 * except in compliance with the License.  
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
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 *-------------------------------------------------------------------------------
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/*! \file snow3g.h
* \brief
* \author Open source Adapted from Specification of the 3GPP Confidentiality and
*          Integrity Algorithms UEA2 & UIA2. Document 2: SNOW 3G Specification
* \integrators  Kharbach Othmane, GAUTHIER Lionel.
* \date 2014
* \version
* \note
* \bug
* \warning
*/
#ifndef FILE_SNOW3G_SEEN
#define FILE_SNOW3G_SEEN

typedef struct snow_3g_context_s {
  uint32_t LFSR_S0;
  uint32_t LFSR_S1;
  uint32_t LFSR_S2;
  uint32_t LFSR_S3;
  uint32_t LFSR_S4;
  uint32_t LFSR_S5;
  uint32_t LFSR_S6;
  uint32_t LFSR_S7;
  uint32_t LFSR_S8;
  uint32_t LFSR_S9;
  uint32_t LFSR_S10;
  uint32_t LFSR_S11;
  uint32_t LFSR_S12;
  uint32_t LFSR_S13;
  uint32_t LFSR_S14;
  uint32_t LFSR_S15;

  /* FSM : The Finite State Machine has three 32-bit registers R1, R2 and R3.
  */
  uint32_t FSM_R1;
  uint32_t FSM_R2;
  uint32_t FSM_R3;
} snow_3g_context_t;

/* Initialization.
* Input k[4]: Four 32-bit words making up 128-bit key.
* Input IV[4]: Four 32-bit words making 128-bit initialization variable.
* Output: All the LFSRs and FSM are initialized for key generation.
*/
void snow3g_initialize(uint32_t k[4], uint32_t IV[4], snow_3g_context_t *snow_3g_context_pP);

/* Generation of Keystream.
* input n: number of 32-bit words of keystream.
* input z: space for the generated keystream, assumes
* memory is allocated already.
* output: generated keystream which is filled in z
*/

void snow3g_generate_key_stream(uint32_t n, uint32_t *z, snow_3g_context_t *snow_3g_context_pP);

#endif
